Use the force
If you practice jhāna correctly according to the suttas, the force is always with you and it grows exponentially.
The jhān-o-meter: why should you use the force? because it's tangible proof of passadhi sambojjhanga
Stories of jhanic force
General principles of meditation
🔗📚: collection of articles for an eventual book, "Jhāna Passaddhi Baselines"